1. Field of the Invention
This invention relates to a ring joint for a seatbelt system used in a seatbelt system for protecting an occupant in an emergency situation of a vehicle, for connecting an inner webbing to an outer webbing.
2. Description of the Prior Art
A ring joint has been used in a seatbelt system having an outer webbing and an inner webbing, and is of such an arrangement that a joint base is secured to the forward end portion of the inner webbing through a lock member and the intermediate portion of the outer webbing is wound round this joint base and turned back thereat.
This lock member is separated from a contact portion of the outer webbing in the normal running condition of a vehicle, and consequently, when the webbings are fastened about an occupant, the lap restraining portion and the shoulder restraining portion of the outer webbing are accomodated in length with each other, so that the webbings can be suitably fastened about the occupant at all times even if any occupant being different in physical build from one another enters the vehicle, or the occupant changes his driving posture. Furthermore, in an emergency situation of the vehicle, such as a collision, the lock member locks the contact portion of the outer webbing between the ring joint and itself due to a tension of the inner webbing, whereby the lengths of the lap restraining portion and the shoulder restraining portion of the outer webbing are made definite, so that the occupant can be suitably restrained.
However, with the ring joint of the type described, when an unbalanced load acts thereon in an emergency situation of the vehicle, the ring joint rotates about a longitudinal axis of one of the webbings, whereby a load in the widthwise direction of the webbing is generated between the ring joint and the webbing, so that the inner webbing moves the lock member in the widthwise direction of the webbing, thus possibly causing the lock member to fall off the joint base.